The tightening of online censorship comes as China steps up security ahead of the Communist Party’s national congress which is held every five years.

“The run-up period to a gathering is a normally a time of greater restrictions of all kinds to assure that the critical Party Congress is held under ideal social conditions and is not disrupted”, Robert Lawrence Kuhn, long-time advisor to China’s leaders and multinational corporations told the BBC.

However, he said it is not yet clear whether the restrictions will be relaxed as has happened after previous party congresses, adding that many analysts do not believe they will be.

data-ad-format="auto">

Cyber security experts said WhatsApp most likely came under the attention of China’s censors because it has a strong reputation for security.

The app provides end-to-end encryption which ensures only the sender and recipient can view the content of messages.

It also prevents Facebook from knowing what is said in any text, voice and video conversation being communicated on WhatsApp.

“China has shown little tolerance to encryption especially on platforms that can be used to share materials or potential propaganda,” Bill Taylor-Mountford, Asia Pacific vice president for LogRhythm told the BBC.

Tech fines

The latest disruption to WhatsApp appears to be part of a broader crackdown on the internet and online content in China.

On Monday, China’s cyber watchdog handed down maximum penalties to some of the country’s top technology firms including Tencent, Baidu and Weibo for failing to properly censor online content.

The penalties were imposed for failing to remove fake news and pornography, as well as content that authorities said “incites ethic tension” and “threatens social order”.